Apparatus for transferring sheets in register within a printing press



' June 25,1968 T. SCHWABACH 3,389,657

APPARATUS FOR TRANSFERRING SHEETS REGISTER WITHIN A PRINTING PRES FiledJune 2, 1966 2 Sheets-Sheet 1 June 25, 1968 'r SCHWABACH 3,389,657

APPARATUS FOR TRANSFERRING SHEETS IN REGISTER WITHIN A PRINTING PRESSFiled June 2, 1966 2 Sheets-Sheet 2 United States Patent 3,389,657APPARATUS FOR TRANSFERRING SHEETS IN REGISTER WITHIN A PRINTING PRESSTeo Schwabach, Wurzburg, Germany, assignor to SchnellpressenfabrikKoenig & Bauer Aktiengesellschaft, Wurzburg, Germany Filed June 2, 1966,Ser. No. 554,738 6 Claims. (Cl. 101-232) ABSTRACT OF THE DISCLOSURE Theinvention consists of a gripper unit for sheets mounted on a link chainconveyor, which unit can be rigidly latched to the chain sprocket driveshaft during sheet transfer. This is done by holding a roller attachedto the gripper unit in a three point contact by V-shaped supportsattached to arms mounted on the drive shaft and by a moveable hook. Thegripper unit also has set screws on either side of the roller to engagethe arms and prevent rocking.

The present invention relates to an apparatus for transferring sheets inexact register from one printing cylinder of a printing press to anotherby means of a gripper chain so that especially for the purpose ofmulti-color printing the same points on each sheet will be locatedprecisely in the same positions on the different printing cylinders.

It is the principal object of the invention to provide a gripper chaincomprising a pair of parallel endless link chains and gripper elementsthereon, and associated apparatus which cooperate with the gripperelements of this chain for insuring that the sheet transfer from oneprinting cylinder to the gripper chain and from the latter to anotherprinting cylinder will always occur in a register as precise as it haspreviously not been possible to attain by similar apparatus which weredeveloped prior to this invention.

For attaining this object, the invention provides that the sheettransfer occurs entirely independently of the inaccuracies of theconstruction and movement of the two link chains and that for thispurpose during the time of each sheet transfer from the printingcylinder to the gripper chain the supporting means of the gripperelements which are mounted on the chains are positively locked bysuitable means in the most suitable position to the solid drive shaftsof the sprocket wheels for the chains so that the particular position ofthe gripper elements depends during this time upon the accurate rotationof these shafts and is not affected by the inaccurate movements of thechains. Consequently, the accurate position of the gripper elements atthe time of each sheet transfer will also not be affected by thecentrifugal forces which act upon the chains and the gripper systemsthereon especially when these chains are driven at a very high speed.Since the supporting means of the gripper elements are securely lockedin a fixed position to the shafts of the sprocket chains at the momentof each sheet transfer, there is also no longer any need to make thesesupporting means of an extremely solid and heavy construction as it wasnecessary in previous apparatus of this type in order to prevent thesesupporting means from being bent or displaced in the operation of theprinting press.

According to the invention, the gripper elements comprise severalparallel rows or systems of tonglike grippers each of which consists ofan arm which is pivotable relative to a fixed abutment. The gripper armsof each system are secured to a common shaft which is cam-controlled soas to be rotated back and forth to pivot all of the gripper arms inunison relative to their opposite abutment and to grip the end of asheet on a printing cylinder substantially at the same time when thisend is released from the printing cylinder by similar grippers or othersuitable means. The opposite ends of this gripper shaft are rotatablymounted in bearing means which according to the invention are preferablyof a resilient construction .and secured to one side of each of the twochains. These bearing means for each gripper system may consist, forexample, of a pair of parallel bearing plates in which the opposite endsof the mentioned gripper shaft are rotatably mounted and which arerigidly connected to each other at least by a bar or rod on which thegripper abutments are mounted. These bearing plates may either consistof a resilient material or, more preferably, each of them may beprovided with a pair of bushings of soft rubber or similar material intowhich the extended ends of two of the link pins of one of the linkchains are inserted.

The above-mentioned locking means for locking each gripper system duringthe short period of the sheet transfer to the drive shaft of the twochains essentially consist according to the invention of at least onecrossbar which rigidly connects the bearing plates to each other andcarries the gripper abutments, of several supporting elements which aremounted on this crossbar at suitable distances from each other and alsoserves as additional intermediate bearing means for the gripper shaft,of a supporting and locking roller which is rotatably mounted on each ofthe supporting elements, of a plurality of prismatic bearings which areadapted to receive the locking rollers when the gripper system islocated in its sheet transfer position and are rigidly secured to thedrive shaft by being mounted on arms which are secured to and projectlaterally from the drive shaft, of a pair of setscrews which areadjustably mounted on each supporting element at both sides of thelocking roller and engage upon the end surface of the associated arm onthe drive shaft and maintain the supporting element and the grippersystem in the proper angular position in the peripheral direction of thedrive shaft, and of a cam-controlled locking member which is adapted tolock the supporting element and the gripper system thereon in a fixedposition to the prismatic bearing and thereby to the drive shaft duringthe period of the sheet transfer. This locking member may, for examplebe hook-shaped and pivotable about an axis which in the sheet transferposition intersects a plane which extends through the axes of thesprocket-wheel drive shaft and the locking roller and also substantiallythrough the axis of the printing cylinder. In order to exert thenecessary pressure upon the locking roller so as to press the samefirmly upon the prismatic bearing and thus to attain a securethree-point support for the locking roller, this locking member mayeither possess a small amount of resilience or exert a slight wedgingaction upon the locking roller. The mentioned setscrews generally needto be adjusted only once during the normal life of the chains and theentire gripper systems, and they insure that these systems will remainin their proper adjustment during this entire length of time. Thus, whenit becomes necessary to readjust the length and tension of the chains,there will be no need also to readjust the gripper systems in order toinsure that the sheet will be transferred in exact register from oneprinting cylinder to another.

The locking mechanism as previously described therefore maintains thegripper system at every sheet transfer in an absolutely fixed positionwithout play in any direction and it insures an exact register even forthe most difficult forms, fine screens and multicolor prints. Thegripper systems which are carried by the two chains and may be of anydesired number may be very accurately adjusted at the place ofmanufacture of the printing press and they do not need to be againadjusted during the life time of the chains since any changes in lengthof the chains or any wear upon the individual elements of the grippersystems will not affect the proper adjustment and positioning of thesesystems during the sheet transfer. The gripper systems will even be inexact regis tcr if the rotation of the printing press is reversed. Thepresent invention is primarily concerned with attaining an exactregistry in the sheet transfer in the direction of travel of the chainsand sheets since it does not involve any particular difficulties toadjust the gripper systems also in lateral directions shortly beforethey are locked in the manner as described.

The features and advantages of the present invention will become furtherapparent from the following detailed description of one preferredembodiment thereof which is to be read with reference to theaccompanying, partly diagrammatic drawings, in which FIGURE 1 shows,partly in section, a side view of one of the gripper systems in thesheet transfer position, while FIGURE 2 shows, partly in section andpartly broken away, a top view of the gripper system according to FEGURE1.

In these drawings, FIGURE 1 shows one of the gripper systems accordingto the invention in the sheet transfer position adjacent to the printingcylinder 1 of a printing press which is merely indicated by an arcuateline. A pair of sprocket wheels 2, as indicated in FIGURE 1 by adot-and-dash line, are rigidly secured to a drive shaft 4 and carry apair of endless link chains 3. Both of these chains 3 carry on theirinner sides facing each other a series of bearing plates incorresponding positions. They are spaced from each other at a distanceequal to the circumference of the printing cylinder. These bearingplates 9 are resiliently mounted on the two chains 3 and are for thispurpose provided with bores in which bushings 21 of soft rubber or asimilar material are secured which are mounted on extensions it) of someof the link pins of each chain 3. Bearing plates 9 are provided withbores or bearings for rotatably mounting the outer ends of a shaft 5,and they are rigidly secured to each other by a rod 6 and preferably inaddition by an angle iron 27. As illustrated in FIGURE 2, shafts 5 androd 6 carry at their center and at equal distances from their ends threesupporting plates 12, each of which is provided with a bore in which theshaft 14 of a ground locking roller 15 is mounted which is freelyrotatable as long as it is not in its locked position, as subsequentlydescribed. Shaft 5 carries a row of grippers '1" and is adapted to berotated back and forth by being provided with an arm, not shown, whichis acted upon by a cam plate, likewise not shown, so as to pivot thesegrippers back and forth relative to fixed abutments 8 on rod 6. Betweenthe circular ends of the printing cylinder, as indicated by the arcuateline 1 in FEGURE 1, this cylinder is provided with a longitudinalrecess, not shown, into which the row of grippers 7 engages when duringthe continuous movements of the printing cylinder and the chains 3 theopened grippers approach the sheet transfer position, as shown in F1 URE1, in which the end of the sheet is released from the printing cylinderby similar grippers or other suitable holding rneans and is grippedsubstantially at the same time between the ends of the grippers 7 andthe abutments 8.

When the row of grippers 7 arrives in the sheet transfer position, theaxes of drive shaft 4, shafts 14 of rollers 15, and rod 6 which carriesthe abutments t are located substantially within the same plane whichthen also substantially intersects the axis of the printing cylinder 1.Drive shaft 4 also also rigidly secured thereto three supporting arms 17in alignment with the three supporting plates 12 (and therefore notvisible in the top view according to FIGURE 2). Each of these arms l7carries rigidly on one side thereof a prismatic bearing 16 which. islocated Within the plane of travel of the associated locking roller 15.When the gripper system approaches the sheet transfer position, as shownin FIGURE 1, the three locking rollers 15 slide from above like groundteeth into the prismatic bearings 16 and rest on the opposite surfacesthereof which thereby support the entire gripper system. When thelocking rollers 15 are in this position, their ends laterally projectbeyond the prismatic bearings 16 and will then be immediately pressedinto locking engagement with the bearing surfaces by hooks 18 which aresecured to a. shaft 19 which is rotatably mounted in the supporting arms17 and the axis of which is likewise disposed within the common planewithin which the axes of shafts 4 and 14 and of rod 6 are located whenthe gripper system is in its sheet transfer position. Shaft 19 isprovided with a laterally projecting arm, not shown, which is acted uponby a cam plate, likewise not shown, so as to pivot the hooks 18 fromtheir open position as shown in FIGURE 1 in dotand-dash lines to theirlocking or sheet-transfer position as shown in dotted lines. in order toexert the necessary locking pressure upon the rollers 15, hooks 13 maybe either slightly resilient or they may exert a slight wedging actionupon the rollers 15 when they are pivoted to their locking position.During the sheet transfer, not only the two outer locking rollers 15 arethus rigidly clamped to the drive shaft 4, but also the central lockingroller 15 so that there is no danger that the gripper system might beaffected by the centrifugal forces acting thereon and that due to theseforces the sheets might not be transferred in exact register from oneprinting cylinder to the other. Since the entire gripper system is thussecurely locked to the solid drive shaft 4 on which the sprocket wheelsfor driving the chains 3 are mounted, this entire system including thegripper shaft 5 and the supporting rod 6 may be made of a very lightconstruction.

In order to adjust and maintain the bearing plates 9 and thus the entiregripper system also in the proper fixed position in the peripheraldirection of the drive shaft 4 and the sprocket wheels 2 thereon so thatthe grippers 7 and their associated abutments 8 will always be in theproper gripping position at the moment of the sheet transfer, the bottomside of each supporting plate 12 is provided at the opposite sides ofthe locking roller 15 with a pair of setscrews 23 and 24 which duringthe period of the sheet transfer solidly en age upon the end surfaces ofa pair of projections 25 and 26 on one of the supporting arms 17 whichare secured to the drive shaft 4.

The purpose of mounting the bearing plates 9 on the links pins 10 of thechains 3 by means of the rubber bushings 21 is primarily to compensatefor the changes in the angular position of these links pins relative toeach other and to the bearing plates, if they consist of a rigidmaterial, and further to compensate for unavoidable play due toinaccuracies of manufacture of the gripper system and to reduce thenoise of operation of the gripper system.

The necessary cam plates for controlling the movements of the grippershaft 5 and the hooks 18, as well as the arms on shafts 5 and 19 whichare acted upon by these cam plates so as to pivot these shafts abouttheir axes are not illustrated in the drawings since they would renderthese drawings too complex and also since they are obvious to any personwho is skilled in the art .of the transmission of movements.

Although my invention has been illustrated and described with referenceto the preferred embodiment thereof, I wish to have it understood thatit is in no way limited to the details of such embodiment but is capableof numerous modifications within the scope of the appended claims.Having thus fully disclosed my invention, what I claim is:

1. In combination with a printing press having a plurality of printingcylinders, an apparatus for transferring sheets in exact register fromone of said cylinders to another comprising a plurality of drive shafts,a pair of sprocket wheels secured to each drive shaft, a pair of endlesslink chains .on said sprocket wheels, a plurality of bearing elementsforming pairs mounted in corresponding positions on said chains at thesides thereof facing each other, at least one crossbar rigidlyconnecting each pair of bearing elements to each other, a gripper shaftrotatably mounted at its opposite ends on said pair of bearing elements,a plurality of grippers secured to said gripper shaft, fixed abutmentsmounted on said crossbar and associated with said grippers for receivingand gripping the end of a sheet coming from an adjacent printingcylinder during the rotation thereof, means for turning said grippershaft back and forth for pivoting said grippers relative to saidabutments, a plurality of supporting elements secured to said crossbarand laterally spaced from each other between said bearing elements, saidgripper shaft extending through and being rotatably mounted by saidsupporting elements, a roller rotatably mounted on each of saidsupporting elements and centrally on one side thereof opposite to theside on which said abutments are located and extending parallel to saidsupporting bar and to said gripper shaft, a plurality of supporting armsequal to the number of said supporting elements rigidly secured to saiddrive shaft, a prismatic bearing secured to each of said supporting armsand having two bearing surfaces disposed at an angle to each other andadapted to receive said roller mounted on the associated supportingelement when said grippers on said supporting elements are substantiallyin their sheet transfer position, bracing means on each of saidsupporting elements at both sides of said roller adapted in said sheettransfer position to engage upon the end of said supporting arm whensaid roller engages with and rests at two sides upon said bearingsurfaces of said prismatic bearing, a locking element adapted to bemoved into engagement with a third side of said roller and to press saidroller in said sheet transfer position upon said two bearing surfaces ofsaid prismatic bearing, and means for moving said locking element intoand out of engagement with said roller.

2. An apparatus as defined in claim 1, in which each of said lockingelements consists of a hook-shaped members, said means for moving saidlocking element comprising a locking shaft rotatably mounted in all ofsaid supporting arms, said hook-shaped members being secured to saidlocking shaft, said locking shaft having an axis disposed substantiallywithin a common plane extending through the axes of said drive shaft,said rollers, and said printing cylinder, and through the center of saidabutment when said grippers are substantially in their sheet transferposition, and means for rotating said locking shaft back and forth forpivoting said hook-shaped members into and out of engagement with saidrollers.

3. An apparatus as defined in claim 1, in which said bracing meanscomprise a pair of setscrews for adjusting the angular position of eachof said supporting elements relative to said drive shaft in theperipheral direction thereof.

4. An apparatus as defined in claim 1, in which each of said bearingelements which is connected to one of said chains is at least partlyresilient so as to adapt itself to the angular displacements of thelinks of said chain relative to each other.

5. An apparatus as defined in claim 1, in which each of said chainscomprises link pins projecting from one side of said chain, each of saidbearing elements comprising a plate containing soft-rubber socketsmounted on at least two of said link pins.

6. An apparatus as defined in claim 1, in which said supporting elementson said crossbar, the associated supporting arms on said drive shaft andsaid prismatic bearings thereon, and the associated locking elements aremounted at substantially equal distances from each other along thelength of said shafts so as to support and lock said gripper shaft at aplurality of points along its length on said drive shaft.

References Cited UNITED STATES PATENTS 1,093,152 4/1914 Smith et a1.198-180 X 2,815,208 12/1957 Wood 271- 2,821,390 1/1958 Norton 271453,167,006 1/1965 Peyrebrune 101-183 ROBERT E. PULFREY, Primary Examiner.

E. H. EICKHOLT, Assistant Examiner.

